The press to which the invention is applied is a press having a press support, which guides a movable press frame, and supports a press bed. These are interconnected by means of a mechanical drive, preferably a toggle lever drive, to form a main press ram. Such a press may further be provided with an auxiliary bottom ram capable of serving as a smoothing ram or a plunger ram for the press bed and which can be operated by means of a lever pivotally mounted within the press support and driven by a mechanical drive, such as a cam drive.
Presses of this general type have already been developed and are described in the European Patent Application Nos. 87/106634.6 and 87/112788.2, for example.
Presses developed along these lines not only assure consistently reproducible operation of all interacting press axes, but may at the same time be operated at a relatively high stroke rate. Furthermore, a high degree of inherent stability of the entire press system at a consistently high degree of operational safety is obtained.
It is of particular advantage that such a press system, while using an already existing toggle press, can be enhanced by integrating additional hydraulic press elements. In this manner, possibilities for flexible movement and drive are obtained for the individual press axes, as well as pressure-independent path control of the same.
According to the European Patent Application No. 87/106634.6, the mechanical press element of the press, i.e., the press bed, is already provided with an additional bottom ram which can be operated by means of a mechanical drive of the cam type. This bottom ram forms the so-called G-press axis, which makes it possible to operate the press in accordance with the so-called plunger process or in accordance with the so-called smoothing process, wherein the bottom ram either forms the press plunger or the press smoothing ram.